package com.naiterui.ehp.bp.utils.lang;

import java.io.ByteArrayInputStream;
import java.io.File;
import java.io.FileInputStream;
import java.io.IOException;
import java.io.InputStream;

import org.springframework.util.Assert;
import org.springframework.util.FileCopyUtils;
import org.springframework.web.multipart.MultipartFile;

/**
 * <pre>
 *     file 转 MultipartFile
 * </pre>
 *
 * @author 王泽浩
 */
public class File2MultipartFileUtil {

    /**
     * <pre>
     *     将file 转换成MultipartFile
     * </pre>
     *
     * @param file
     *
     * @return
     */
    public static MultipartFile convert(File file) throws IOException {
        return new ConvertMultipartFile(file.getName(), new FileInputStream(file));
    }

    /**
     * 此类复制MockMultipartFile
     */
    @SuppressWarnings("unused")
    public static class ConvertMultipartFile implements MultipartFile {

        private final String name;

        private String originalFilename;

        private String contentType;

        private final byte[] content;

        /**
         * Create a new ConvertMultipartFile with the given content.
         *
         * @param name    the name of the file
         * @param content the content of the file
         */
        public ConvertMultipartFile(String name, byte[] content) {
            this(name, "", null, content);
        }

        /**
         * Create a new ConvertMultipartFile with the given content.
         *
         * @param name          the name of the file
         * @param contentStream the content of the file as stream
         *
         * @throws IOException if reading from the stream failed
         */
        public ConvertMultipartFile(String name, InputStream contentStream) throws IOException {
            this(name, "", null, FileCopyUtils.copyToByteArray(contentStream));
        }

        /**
         * Create a new ConvertMultipartFile with the given content.
         *
         * @param name             the name of the file
         * @param originalFilename the original filename (as on the client's machine)
         * @param contentType      the content type (if known)
         * @param content          the content of the file
         */
        public ConvertMultipartFile(String name, String originalFilename, String contentType, byte[] content) {

            Assert.hasLength(name, "Name must not be null");
            this.name = name;
            this.originalFilename = originalFilename != null ? originalFilename : "";
            this.contentType = contentType;
            this.content = content != null ? content : new byte[0];
        }

        /**
         * Create a new ConvertMultipartFile with the given content.
         *
         * @param name             the name of the file
         * @param originalFilename the original filename (as on the client's machine)
         * @param contentType      the content type (if known)
         * @param contentStream    the content of the file as stream
         *
         * @throws IOException if reading from the stream failed
         */
        public ConvertMultipartFile(String name, String originalFilename, String contentType, InputStream contentStream) throws IOException {

            this(name, originalFilename, contentType, FileCopyUtils.copyToByteArray(contentStream));
        }

        @Override
        public String getName() {
            return this.name;
        }

        @Override
        public String getOriginalFilename() {
            return this.originalFilename;
        }

        @Override
        public String getContentType() {
            return this.contentType;
        }

        @Override
        public boolean isEmpty() {
            return this.content.length == 0;
        }

        @Override
        public long getSize() {
            return this.content.length;
        }

        @Override
        public byte[] getBytes() {
            return this.content;
        }

        @Override
        public InputStream getInputStream() {
            return new ByteArrayInputStream(this.content);
        }

        @Override
        public void transferTo(File dest) throws IOException, IllegalStateException {
            FileCopyUtils.copy(this.content, dest);
        }

    }

}
